Fig. 4. Detachment of mural cells from endothelial sheets by exogenous PDGF-BB or anti-PDGFRß neutralizing antibody (APB5). (A-C) PDGF-BB (20 ng/ml; A) or anti-PDGFRß neutralizing antibody (APB5, 50 µg/ml; C) was added to cells cultured with VEGF-A and FGF-2 (B). Green: expression of PECAM1; red: SMA; purple: nuclear counterstain. Arrows in A and C indicate detached mural cells; arrowheads in B indicate attached mural cells. Scale bars: 100 µm. (D) Bar chart of distances between the nearest edges of SMA⁺ mural and PECAM1⁺ endothelial sheets. Frequency is shown as the percentage of SMA⁺ cell present in each distance class. (E) Comparison of the rates of appearance of PECAM1⁺ and SMA⁺ cells.